The invention relates generally to filtering and sensing within a power converter. Particularly, this invention relates to a DC link inductor that is integrated with a sensor winding.
A DC link or bus in a power converter conducts DC power that the power converter converts into AC power at a desired frequency, which may be applied to drive an electric motor, among other things. A DC link inductor often includes a variety of windings or coils for performing various sensing and control functions. For example, a DC link may include a pair of inductors on each primary current path, and one or more windings to detect ground faults. The inductors on the primary current paths filter and smooth the primary DC currents, and the windings for detecting ground faults typically sense the relative magnitude of currents on the primary current paths. To identify a ground fault, the currents from each path are compared, and a determination is made whether the same amount of current is flowing into a load connected to the DC link as is flowing out of the load. If substantially more current flows into a load than out of a load, a ground fault may have occurred.
Unfortunately, the large number of discrete windings in traditional DC links can have undesirable effects. For example, the inductors often include large, heavy cores that can increase the size and weight of a DC link. Having several discrete inductors in a DC link may amplify the impact of these devices on the total size and weight of the DC link, thereby potentially increasing material, shipping, and storage costs.
There is a current need in the art, therefore, for an improved DC link.